Dell's earliest venture into paperback publishing began because of its close association with Western Publishing. "... Dell needed paper, which Western had in 1942, and because Western by this time needed printing work, which Dell could supply in the form of its new paperback line. So Dell Books was born, created by Delacorte of Dell and Lloyd E. Smith of Western." (Putting Dell on the Map, William H. Lyles, Greenwood Press, 1983) Dell began publishing paperbacks in 1942 at a time when mass-market paperbacks were a relatively new idea for the United States market — its principal competitor, Pocket Books, had only been publishing since 1939. An examination of paperback books available at this time shows no consensus on standardization of any feature; each early company was attempting to distinguish itself from its competitors. "Dell achieved more variety than any of its early competitors. It did so, at first, with an instantly identifiable format of vibrant airbrushed covers for its predominantly genre fiction, varying "eye-in-keyhole" logos, maps on the back covers, lists of the books' characters, and "tantalizer-pages". The design was merchandising genius; it successfully attracted buyers, it sold books." (ibid)

The first four books did not feature maps on the back cover; this began with Dell #5, Four Frightened Women by George Harmon Coxe. (A later re-issue of Dell #4, The American Gun Mystery by Ellery Queen, added a map.) The map was meant as an aid to the reader, to show the location of the principal activity of the novel. Some were incredibly detailed; others somewhat stylized and abstract. The books were almost immediately known as "mapbacks", and that nomenclature has lasted among collectors to this day. The maps were "delicate and detailed". (Hancer's Price Guide to Paperback Books, Third Edition, ed. Kevin Hancer, Wallace-Homestead, 1990)

The novels in the mapback series were primarily mysteries/detective fiction, but ran the gamut from romances (Self-Made Woman by Faith Baldwin, #163) to science fiction (The First Men in the Moon by H.G. Wells, #201), war books (I Was A Nazi Flyer by Gottfried Leske, #21 and Eisenhower Was My Boss by Kay Summersby, #286), many westerns (Gunsmoke and Trail Dust by Bliss Lomax, #271), joke books (Liberty Laughs, Cavanah & Weir, #38), and even crossword puzzles (Second Dell Book of Crossword Puzzles, ed. Kathleen Rafferty, #278, one of the rarest titles today). There were a few movie tie-in editions (The Harvey Girls by Samuel Hopkins Adams, #130, and Rope as by Alfred Hitchcock, #262) and the occasional attempt at more artistic non-genre fiction (To A God Unknown by John Steinbeck, #407). Novels which are today long forgotten, by largely unknown authors (Death Wears A White Gardenia, by Zelda Popkin, #13) are in the same series as valuable original paperback editions of famous authors (A Man Called Spade, by Dashiell Hammett, #90). "The back cover map was very popular with readers and remains popular with collectors ... the Dell "mapbacks" are among the most well-known vintage paperbacks." (Canja, Jeff)

In the early 1950s, as series numbering reached the 400s, Dell began updating the appearance of its books. In 1951, the back cover maps began to be gradually replaced with conventional text and "blurb" covers. (Canja, Jeff) Some later, more stylized maps were the product of Milton Glaser and Push Pin Studios.

At about this time, Dell launched two short-lived experiments which are also considered very collectible, Dell First Editions and Dell Ten Cent Books. The Ten Cent Books, 36 in all, were paperback-sized editions containing a single short story told in only 64 pages (advertised as, "too short for popular reprint at a higher price"). Dell First Editions included novels (first editions, of course) by John D. MacDonald, Fredric Brown, Jim Thompson, Elmore Leonard, and Charles Williams, among many others. "In 1947 Dell published two un-numbered paperbacks based on newspaper comic strips, Blondie and Dagwood in Footlight Folly and Dick Tracy and the Woo Woo Sisters. Both of these are quite scarce and very popular with collectors today."(Canja, Jeff)

Dell Publishing no longer exists as an independent entity. They were bought out and are part of the "Bantam Dell Publishing Group" of Random House, which also uses some of Dell's other imprints. Dell Magazines was sold in 1997, and is still exists as a major publisher of puzzle magazines, publishing science fiction, mystery, and horoscope magazines.